Many methods for displaying color information on display devices are known in the art. Most computer systems utilize RGB (red green blue) techniques wherein color information is processed as three separate digital units of color information for each displayed pixel. For example, in a typical 24 bit RGB computer system, 8 bits describe the intensity of a red color gun of a display, 8 bits describe the intensity of a green color gun of the display, and 8 bits describe the intensity of a blue color gun of the display for a total of over 16 million possible colors for each displayed pixel.
Due to the requirements of most computer displays, computer systems typically utilize a frame buffer to store the digital color information for each pixel. The frame buffer is then continuously scanned for displaying the pixel information on the display. In addition, the frame buffer is updated as needed by the computer system to modify the displayed information. However, for high resolution color systems, such as a display with 1280.times.1024 pixels and 24 bit color, a video look up table (LUT) is often utilized to lower the memory requirements for the frame buffer. When a LUT is utilized, the frame buffer stores indexes to the LUT rather than the actual displayed colors. The LUT stores a the actual pixel colors, called a color palette, at locations addressed by the indexes stored in the frame buffer. For example, the frame buffer may store an 8 bit index which is used to read a 256 entry LUT. The LUT then provides the 24 bit color for that index. Although this limits the total number of colors that can be displayed at any given time (256 colors in this example) this technique retains the total possible color palette of over 16 million colors.
There are several techniques for determining which colors will be stored in the video LUT. Some systems utilize a fixed LUT such that there are a small fixed number of colors that may be utilized. Some systems utilize a fixed LUT for a given application or set of images. Other dynamic systems allow a LUT to be generated for each image being displayed.